It needs a lot of polish, but it's a nice start.
Off the top of my mind, there's a few I can think of:
- Add some audiovisual feedback for when the barn takes damage. As it is, the only way to see if it took damage is to look at the number.
- Some audiovisual feedback for reloading would be nice too. Just a sound effect, and the ammo count flashing somehow (just make the ammo count get big then small again, that should work).
- The music just stops after a while instead of looping. That is rather jarring.
- Opening the barn screen clears all enemies on screen for free, which makes the game rather easy. Look into preserving the shooter scene when opening the barn scene.
- If you leave the barn screen with 0 ammo, the game allows you to shoot anyway, which puts the ammo in the negatives and allows you to shoot indefinitely.